The calculator tool has a well-defined schema with proper JSON Schema structure, good naming conventions, and adequate descriptions. However, there are significant limitations: (1) only one tool is present, limiting composition assessment; (2) parameter descriptions are missing from the schema definition, which violates the pattern that EVERY parameter needs a description; (3) output schema is not explicitly documented; (4) error handling is basic (division by zero check exists, but responses lack recovery guidance); (5) no indication of idempotency or destructive operation hints. The tool itself is simple and well-intentioned, but falls short of production-grade quality due to undocumented parameters and missing output schema documentation.

• Add 'description' field to each parameter in the input schema. Example: {"operation": {"type": "string", "enum": [...], "description": "The arithmetic operation to perform: add, subtract, multiply, or divide"}, ...}
• Document the output schema explicitly. Add a comment or schema field showing: {"type": "number", "description": "The numeric result of the operation"} or similar, depending on actual output format.
• Enhance error messages with recovery guidance and error classification. For division by zero, return: {"error": "Division by zero. The divisor (parameter 'b') must be non-zero. Please retry with a different value." } and classify as 'user-fixable'.
• Add tool annotations to the ToolInfo struct if the framework supports it. Include readOnlyHint=true and idempotentHint=true to signal to agents that this tool is safe to retry and does not modify state.
• Add parameter constraints to descriptions. E.g., 'operation (required, one of: add, subtract, multiply, divide)', 'a (required, numeric value)', 'b (required, numeric value; cannot be 0 for divide operation)'.

Inferred effective spec: <=2025-11-25.

• Relies on Logging (deprecated) - log to stderr or use OpenTelemetry